Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 202330
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
630 PM CDT Mon Apr 20 2015
.SHORT TERM...(This Evening through Tuesday Night)
Issued at 250 PM CDT MON APR 20 2015
Surface low pressure is located across the Great Lakes region this
afternoon as high pressure builds across the Plains. As a result
gusty winds have occurred today as the pressure gradient was tight
between the low and high.
This evening and tonight the pressure gradient will relax as the
low pushes off to the east and surface low pressure moves into
central Arkansas. Lows will drop well into the 40s tonight and a
few locations may dip into the upper 30s. Winds will weaken
tonight but will not go claim as the high remains south of the
area. Winds should also remain high enough to limit frost from
An upper level low located across northern Minnesota this
afternoon will push east into the Great Lakes region on Tuesday.
Energy from the low will spread southeast into the region Tuesday
afternoon and evening, sparking off scattered thunderstorms.
Instability will increase some with the heating of the day but
will still remain on the limited side. Given colder temperatures
aloft, a few strong to marginally severe storms with hail to the
size of quarters will be possible. Wind shear will be strong
enough to support a wind risk if any line of storms can develop.
However, theta-E differences will be weak and may be tough to get
any cold pools to congeal into a line, and if they do they may be
shear dominant. Instability will decrease overnight Tuesday with
thunderstorm coverage decreasing.
.LONG TERM...(Wednesday through Monday)
Issued at 250 PM CDT MON APR 20 2015
The area will remain in northwest flow during the middle of this
week with below normal temperatures, and highs in the upper 50s
to lower 60s, and lows in the 40s occurring both Wednesday and
Thursday. A cold front will move south through the area on
Wednesday and generate a few showers across the area as it moves
through the region. The front may try to move back to the north on
Thursday with showers again possible across southern Missouri, but
the better chances will remain south of the area on Thursday.
Shortwave upper level ridging will build over the region and will
likely result in the warmest day of the week on Friday as highs
warm into the middle to upper 60s. An upper level trough and
associated surface low will then track through the region Friday
afternoon into early Saturday and will bring better chances for
showers and a few thunderstorms to the area. No severe weather is
expected at this time.
Another upper level disturbance will track through the region
Sunday into Monday and will bring additional chances for showers
and thunderstorms to the area.
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 630 PM CDT MON APR 20 2015
For the KSGF/KJLN/KBBG TAFS: Pressure gradient was beginning to
relax across the area and winds will continue to diminish at the taf
sites through the early evening hours. With loss of heating
strato-cumulus will also dissipate with clear skies expected through
the evening hours.
However, deep 500mb low will settle over Upper Michigan and lake
Superior later tonight with broad cyclonic flow over southern
Missouri. A weak impulse will ride through the flow late tonight
into Tuesday. A gradual increase in mid and high level moisture will
push into the taf sites ahead of this feature from tonight into
Tuesday morning. Ceilings will lower somewhat after 16Z Tuesday as
weak impulse nears, albeit remaining in the vfr category. Enough
lift looks to be generated for scattered showers and thunderstorms,
especially during the afternoon hours and will handle this with a
prob30 group during the last 3 to 4 hours of the taf forecast. West
to southwest winds will also increase again late Tuesday morning as
gradient tightens and will likely see a west to southwest wind
gusting to 20 to 25 knots during the afternoon hours.